10
1 Redox Proteins and Bioelectrocatalysis
Fig. 1.8 Typical reactions of free PQQ with nucleophiles
NH
O
O
S
H 2 C
NH
CH
C
O
CH 2
NH
CH
C
O
NH
O
NOH
S
H 2 C
NH
CH
C
O
CH 2
NH
CH
C
O
4-nitrophenyl hydrazine
NH 2 OH
amines
reducatants
Fig. 1.9 The structure of an oxime form of CTQ in a silent form of a quinohemoprotein amine
dehydrogenase
1.2.4 Hemes [1, 30]
Iron is the fourth most abundant element in the earth’s crust, and is also the most abundant transition metal found in biological systems. Many iron-containing enzymes
appear to be variants of common structural motifs and undergo single electron transfers in biological processes. The iron-containing protein family constitutes approximately 50 % of all metal-containing redox enzymes, and it is proposed that the family
potentially catalyzed redox reactions in the Archean oceans [31].
One of the common types of a single-electron carrier is heme redox center, which
has a porphyrin ring, comprising four pyrrole rings by methylene bridges, with a
1 Redox Proteins and Bioelectrocatalysis
Fig. 1.8 Typical reactions of free PQQ with nucleophiles
NH
O
O
S
H 2 C
NH
CH
C
O
CH 2
NH
CH
C
O
NH
O
NOH
S
H 2 C
NH
CH
C
O
CH 2
NH
CH
C
O
4-nitrophenyl hydrazine
NH 2 OH
amines
reducatants
Fig. 1.9 The structure of an oxime form of CTQ in a silent form of a quinohemoprotein amine
dehydrogenase
1.2.4 Hemes [1, 30]
Iron is the fourth most abundant element in the earth’s crust, and is also the most abundant transition metal found in biological systems. Many iron-containing enzymes
appear to be variants of common structural motifs and undergo single electron transfers in biological processes. The iron-containing protein family constitutes approximately 50 % of all metal-containing redox enzymes, and it is proposed that the family
potentially catalyzed redox reactions in the Archean oceans [31].
One of the common types of a single-electron carrier is heme redox center, which
has a porphyrin ring, comprising four pyrrole rings by methylene bridges, with a